Simulating cosmological supercooling with a cold-atom system

We perform an analysis of the supercooled state in an analog to an early universe phase transition based on a one-dimensional, two-component Bose gas. We demonstrate that the thermal fluctuations in the relative phase between the components are characteristic of a relativistic thermal system. Furthermore, we demonstrate the equivalence of two different approaches to the decay of the metastable state: specifically a nonperturbative thermal instanton calculation and a stochastic Gross-Pitaevskii simulation.